Построение графика функции arccos (k * x)

const double PI = 4.0 * atan (1.0);
   const int LeftBorder = 10;
   const int RightBorder = ClientWidth - 10;
   const int TopBorder = 10;
   const int BottomBorder = ClientHeight - 10;
   TPoint pt [NUM];
 
   Image1 -> Canvas -> Pen -> Color = clGray;
   Image1 -> Canvas -> MoveTo (ClientWidth / 2, 0);
   Image1 -> Canvas -> LineTo (ClientWidth / 2, ClientHeight);
   Image1 -> Canvas -> MoveTo (0, ClientHeight / 2);
   Image1 -> Canvas -> LineTo (ClientWidth, ClientHeight / 2);
 
   const double x1 = -1, x2 = 1;
   const double dx = 0.0001;
   double y1 = acos (x1), y2 = acos (x2), x = x1, y, mx, my;
   int x0, y0;
 
   do {
      y = acos (x);
      if (y < y1) y1 = y;
      if (y > y2) y2 = y;
      x += dx;
   } while (x <= x2);
 
   mx = (RightBorder - LeftBorder) / (2 * PI);
   my = (double)(BottomBorder - TopBorder) / (2 * PI);
 
   x0 = LeftBorder + abs (-PI * mx);
   y0 = BottomBorder - abs (PI * my);
 
   x = x1;
   do {
      y = acos (x);
      Image1 -> Canvas -> Pixels [x0 + x * mx][y0 - y * my] = clRed;
      x += dx;
   } while (x <= x2);